Doug, I haven't tried it for photography. I have experimented with the Kodak color negative film that has an ASA of 800. I have a 205 mm telephoto lens with a 2X adapter which yields a practical aperture of f11. I got very good results. I would assume that the Leica would be an excellent telephoto at 800 mm. Sorry, hope this is helpful. Chris Barnard cbarnard52@aol.com